In recent years, an individual identification technique using wireless communication using an electromagnetic field, a radio wave, or the like has attracted attention. In particular, an individual identification technique with the utilization of an RFID (Radio Frequency IDentification) tag as a semiconductor device which communicates data by wireless communication has attracted attention. The RFID tag (hereinafter, simply referred to as an RFID) is also referred to as an IC (Integrated Circuit) tag, an IC chip, an RF tag, a wireless tag, or an electronic tag. The individual identification technique with the utilization of an RFID has been useful for production, management, and the like of an individual object, and has been expected to be applied to personal authentication.
An RFID can be classified into two types depending on whether a power source is incorporated in the RFID or a power source is supplied from the outside: an active-type RFID capable of transmitting radio waves or electromagnetic waves including information on the RFID, and a passive-type RFID which is driven with the utilization of power of radio waves or electromagnetic waves (carrier waves) from outside (as for the active-type RFID, see Patent Document 1: Japanese Published Patent Application No. 2005-316724 and, as for the passive-type RFID, see Patent Document 2: Japanese Translation of PCT International Application No. 2006-503376). Between the two, the active-type RFID has a structure in which a power source for driving the RFID is incorporated and a battery is provided as the power source. In addition, the passive-type RFID has a structure in which power of radio waves or electromagnetic waves (carrier waves) from the outside is used as a power source for driving the RFID so that a structure without a battery is realized.
FIG. 31 is a block diagram showing a specific structure of an active-type RFID. In an active-type RFID 3100 of FIG. 31, communication signals received by an antenna circuit 3101 are inputted into a demodulation circuit 3105 and an amplifier circuit 3106 in a signal control circuit 3102. Communication signals of 13.56 MHz or 915 MHz are usually transmitted after being processed using ASK modulation, PSK modulation, or the like. Here, in FIG. 31, an example of a 13.56 MHz carrier is shown as the communication signal. In FIG. 31, a clock signal which is a reference for processing a signal is necessary, and a 13.56 MHz carrier is used as a clock here. The amplifier circuit 3106 amplifies the 13.56 MHz carrier and supplies it to a logic circuit 3107 as the clock. In addition, the ASK modulated communication signal or the PSK modulated communication signal is demodulated by the demodulation circuit 3105. The signal which has been demodulated is also transmitted to the logic circuit 3107 to be analyzed. The signal analyzed by the logic circuit 3107 is transmitted to a memory control circuit 3108, and in accordance with the signal, the memory control circuit 3108 controls a memory circuit 3109, and data stored in the memory circuit 3109 is taken out and transmitted to a logic circuit 3110. The signal stored in the memory circuit 3109 is subjected to encode processing by the logic circuit 3110 and then amplified by an amplifier circuit 3111 so that the carrier is modulated by a modulation circuit 3112 with the signal. Here, a power source in FIG. 31 is supplied by a battery 3103 provided outside the signal control circuit through a power source circuit 3104. The power source circuit 3104 supplies power to the amplifier circuit 3106, the demodulation circuit 3105, the logic circuit 3107, the memory control circuit 3108, the memory circuit 3109, the logic circuit 3110, the amplifier circuit 3111, the modulation circuit 3112, and the like. In such a manner, the active-type RFID operates.
FIG. 32 is a block diagram showing a specific structure of a passive-type RFID. In a passive-type RFID 3200 of FIG. 32, a communication signal received by an antenna circuit 3201 is inputted into a demodulation circuit 3205 and an amplifier circuit 3206 in a signal control circuit 3202. The communication signal is usually transmitted after a carrier such as a 13.56 MHz carrier or a 915 MHz carrier is processed using ASK modulation, PSK modulation, or the like. Here, in FIG. 32, an example of a 13.56 MHz carrier is shown as the communication signal. In FIG. 32, a clock signal which is a reference for processing a signal is necessary, and a 13.56 MHz carrier is used as the clock here. The amplifier circuit 3206 amplifies the 13.56 MHz carrier and supplies it to a logic circuit 3207 as the clock. In addition, the ASK modulated communication signal or the PSK modulated communication signal is demodulated by the demodulation circuit 3205. The signal which has been demodulated is also transmitted to the logic circuit 3207 to be analyzed. The signal analyzed in the logic circuit 3207 is transmitted to a memory control circuit 3208, and in accordance with the signal, the memory control circuit 3208 controls a memory circuit 3209, and data stored in the memory circuit 3209 is taken out and transmitted to a logic circuit 3210. The signal stored in the memory circuit 3209 is encoded in the logic circuit 3210 and then amplified in an amplifier circuit 3211 so that a modulation circuit 3212 modulates the signal. On the other hand, the communication signal inputted into a rectifier circuit 3203 is rectified and inputted into a power source circuit 3204. The power source circuit 3204 supplies power to the amplifier circuit 3206, the demodulation circuit 3205, the logic circuit 3207, the memory control circuit 3208, the memory circuit 3209, the logic circuit 3210, the amplifier circuit 3211, the modulation circuit 3212, and the like. In such a manner, the passive-type RFID operates.